1,3-bis[3-(dimethylamino)propyl]urea

Repeated dose toxicity: oral

Administrative data

Endpoint:

repeated dose toxicity: oral, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

The study was designed to investigate the systemic toxicity of the test material and complies with the following guidelines:
i) Commission Directive 96154tEC (Method B7).
ii) The Japanese Ministry of Health and Welfare (MHW) Guidelines 1986 for a twenty-eight day repeat dose oral toxicity study as required by the Japanese Chemical Substances Control Law 1973 of the Ministry of Economy Trade and Industry (METI) amended 1986.
iii) The OECD Guidelines for Testing of Chemicals No. 407 "Repeated Dose 28 Day Oral Toxicity Study in Rodents" (Adopted 28 July 1995).
iv) USA Environmental Protection Agency (EPA) Health Effects Test Guidelines, OPPTS 870.3050 Repeated Dose 28-Day Toxicity Study in Rodents, July 2000.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-(dimethylamino)propylurea

EC Number:

401-950-2

EC Name:

3-(dimethylamino)propylurea

Cas Number:

31506-43-1

Molecular formula:

C6H15N3O

IUPAC Name:

3-dimethylaminopropyl urea

Constituent 2

Reference substance name:

1,3-bis[3-(dimethylamino)propyl]urea

EC Number:

257-861-2

EC Name:

1,3-bis[3-(dimethylamino)propyl]urea

Cas Number:

52338-87-1

Molecular formula:

C11H26N4O

IUPAC Name:

1,3-bis[3-(dimethylamino)propyl]urea

Constituent 3

Reference substance name:

Urea

EC Number:

200-315-5

EC Name:

Urea

Cas Number:

57-13-6

Molecular formula:

CH4N2O

IUPAC Name:

urea

Test material form:

liquid

Specific details on test material used for the study:

Sponsor's identification : 3-DMAPAU
Description : white turbid viscous liquid
Lot number : 18207-61C
Date received : 19 April 2004
Storage conditions : room temperature in the dark under nitrogen

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

A sufficient number of male and female Sprague-Dawley Crl:CD (SD ) BR strain rats were obtained from Charles River (UK) Limited, Margate, Kent. On receipt the animals were examined for signs of ill-health or injury. The animals were acclimatised for ten days during which time their health status was assessed. A total of sixty animals (thirty males and thirty females) were accepted into the study. At the start of treatment the males weighed 180 to 25 lg, the females weighed 141 to 195g, and were approximately five to six weeks old.
The animals were housed in groups of five by sex in polypropylene grid-floor cages suspended over trays lined with absorbent paper. The animals were allowed free access to food and water.
A pelleted diet (Rodent 5LF2 (Certified) Diet, International Product Supplies Ltd., Northants, UK) was used. A certificate of analysis of the batch of diet used is given in Appendix 15. Mains drinking water was supplied from polycarbonate bottles attached to the cage. The diet and drinking water were considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study. Environmental enrichment was provided in the form of wooden chew blocks (B & K Universal Ltd., Hull, UK) and cardboard fun tunnels (Datesand Ltd., Cheshire, UK).
The animals were housed in a single air-conditioned room within the Safepharm Barrier Maintained Rodent Facility. The rate of air exchange was at least fifteen air changes per hour and the low intensity fluorescent lighting was controlled to give twelve hours continuous light and twelve hours darkness. Environmental conditions were continuously monitored by a computerised system, and print-outs of hourly mean temperatures and humidities were included in the study records. The temperature and relative humidity controls were set to achieve target values of 21 h 2•‹C and 55 k 15% respectively. Deviations from these targets were considered not to have affected the purpose or integrity of the study.
The animals were randomly allocated to treatment groups using random letter tables and the group mean bodyweights were then determined to ensure similarity between the treatment groups.
The cage distribution within the holding rack was also randornised. The animals were uniquely identified within the study by an ear punching system routinely used in these laboratories.

Administration / exposure

Route of administration:

oral: gavage

Details on route of administration:

The test material was administered by gavage to three groups, each of five male and five female Sprague-Dawley Cr1:CDB (SD) IGS BR strain rats, for twenty-eight consecutive days, at dose levels of 25,250 and 500 mg/kg/day. A control group of five males and five females was dosed with vehicle alone (distilled water).

Vehicle:

water

Details on oral exposure:

The test material was administered daily, for twenty-eight consecutive days, by gavage using a stainless steel cannula attached to a disposable plastic syringe. Control animals were treated in an identical manner with 5 ml/kg/day of distilled water. Recovery group animals were maintained for a further fourteen days treatment-free period following termination of treatment.
Two recovery groups, each of five males and five females, were treated with the high dose (500 mg/kg/day) or the vehicle alone for twenty-eight consecutive days and then maintained without treatment for a further fourteen days.
The volume of test and control material administered to each animal was based on the most recent bodyweight and was adjusted at weekly intervals

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentration of 3-DMAPAU in the test material formulations was determined by high performance liquid chromatography (HPLC) using an external standard technique. The test material formulations were sampled and analysed within four days of preparation.

Duration of treatment / exposure:

Two recovery groups, each of five males and five females, were treated with the high dose (500 mg/kg/day) or the vehicle alone for twenty-eight consecutive days and then maintained without treatment for a further fourteen days.

Frequency of treatment:

The test material was administered daily, for twenty-eight consecutive days, by gavage using a stainless steel cannula attached to a disposable plastic syringe

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

25 mg/kg bw/day (nominal)

Remarks:

Oral administration of 3-DMAPAU to rats, by gavage, at dose levels of 25,250 and
i 500 mg/kg/day for twenty-eight consecutive days produced no toxicologically significant changes in any of the treatment groups.

Doses / concentrations 2

Dose / conc.:

250 mg/kg bw/day (nominal)

Remarks:

Oral administration of 3-DMAPAU to rats, by gavage, at dose levels of 25,250 and
i 500 mg/kg/day for twenty-eight consecutive days produced no toxicologically significant changes in any of the treatment groups.

Doses / concentrations 3

Dose / conc.:

500 mg/kg bw/day (nominal)

Remarks:

Oral administration of 3-DMAPAU to rats, by gavage, at dose levels of 25,250 and
i 500 mg/kg/day for twenty-eight consecutive days produced no toxicologically significant changes in any of the treatment groups.

No. of animals per sex per dose:

The test material was administered by gavage to three groups, each of five male and five female Sprague-Dawley Cr1:CDB (SD) IGS BR strain rats.

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

All animals were examined fox overt signs of toxicity, ill-health or behavioural change immediately before dosing and one and five hours after dosing during the working week.
Animals were observed immediately before dosing and one hour after dosing at weekends and public holidays. During the treatment-free period, animals were observed twice daily, morning and afternoon (once daily at weekends). All observations were recorded.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

No toxicologically important clinical sings were detected in any animal throughout the study

Mortality:

no mortality observed

Description (incidence):

There were no unscheduled deaths during the study.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No adverse effect on bodyweight development was detected.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

There was no adverse effect on food consumption throughout the study.

Food efficiency:

no effects observed

Description (incidence and severity):

Food efficiency in test animals was similar to that of controls.

Water consumption and compound intake (if drinking water study):

no effects observed

Description (incidence and severity):

Daily visual inspection of water bottles revealed no overt intergroup differences.

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Description (incidence and severity):

No toxicologically significant effects were detected in the haematological parameters measured.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

Blood Chemistry. No toxicologically significant effects were detected in the blood chemical parameters measured.

Urinalysis findings:

no effects observed

Description (incidence and severity):

No treatment-related effects were detected and statistical evaluation of the quantitative data revealed no significant differences.

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

No treatment-related effects were detected.

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

There were no treatment-related changes in the organ weights measured

Gross pathological findings:

not specified

Neuropathological findings:

no effects observed

Description (incidence and severity):

Necropsy. No treatment-related findings were observed.

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

Histopathology. No treatment-related changes were observed.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

Clinical signs, functional observations, bodyweight development and food and water consumption were monitored during the study. Haematology, blood chemistry and urinalysis were evaluated for all surviving non-recovery group animals at the end of the treatment period and for all recovery group animals at the end of the treatment-free period.
All animals were subjected to gross necropsy examination and histopathological evaluation of selected tissues was performed.
Mortality. There were no unscheduled deaths during this study.
Clinical Observations. No toxicologically important clinical sings were detected in any animal throughout the study.
Functional Observations.
Behavioral Assessment. No treatment-related effects were detected.
Functional Performance Tests. No treatment-related effects were detected.
Sensory Reactivity Assessments. No treatment-related effects were detected.
Bodyweight. No adverse effect on bodyweight development was detected.
Food Consumption. There was no adverse effect on food consumption throughout the study. Food efficiency in test animals was similar to that of controls.
Water Consumption. Daily visual inspection of water bottles revealed no overt intergroup differences.
Haematology. No toxicologically significant effects were detected in the haematological parameters measured.
Blood Chemistry. No toxicologically significant effects were detected in the blood chemical parameters measured.
Urinalysis. No treatment-related effects were detected and statistical evaluation of the quantitative data revealed no significant differences.
Organ Weights. There were no treatment-related changes in the organ weights measured.
Necropsy. No treatment-related findings were observed.
Histopathology. No treatment-related changes were observed.

Effect levels

Key result

Dose descriptor:

NOEL

Effect level:

ca. 500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

food efficiency

haematology

histopathology: non-neoplastic

mortality

neuropathology

organ weights and organ / body weight ratios

urinalysis

water consumption and compound intake

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

Oral administration of 3-DMAPAU to rats, bv gavage, at dose levels of 25, 250 and 500 mg/kg/dayv for twentv-eight consecutive days produced no toxicologically significant changes in any of the treatment proups.
The "No Observed Effect Level (NOEL) was, therefore, considered to be 500 mg/kg/day